Hello, Why do we use KVL in Ac circuits ?! or to be more specific is it accurate to use it in Ac circuit , just the same accuracy as using it in Dc ?! Doesn't the current that pass through the circuit itself make it's own variable magnetic field , which crosses the loop of the circle , making ∫E.dl = -d∅/dt , so in the circuit loop we can't say that the field is conservative anymore ?! also we have the Ac source it self , which functions by rotating into the magnetic field or by applying a time changing magnetic field , so if we expand the circuit diagram and instead of putting the famous "shape" of a sinusoidal voltage source , we but the whole device , we will see also varying magnetic field of another magnitude passing through that part of the circuit I may think that the second thing I said is already taken into consideration , and that's why we put a voltage source "shape of a sinusoidal voltage source" I just try to get the whole picture . so , wether we have coils or not in the circuit , doesn't the time-varying current it self make a change to KVL ?!